1. Field of the Present Invention
The present invention relates to a micro electro mechanical device (a micro electronic mechanical system) formed over an insulating substrate. In particular, the present invention relates to a micro mechanical structure of a micro electro mechanical device and a method for manufacturing the micro mechanical structure of the micro electro mechanical device.
2. Description of the Related Art
In recent years, a micro mechanical system called MEMS has been actively researched. MEMS is abbreviation of Micro Electro Mechanical System and translated into a micro electro mechanical device, a micro electro mechanical system, or the like. MEMS is also called a micro machine in Japan and is also called an MST (Micro System Technology) in Europe or the like. In this specification, MEMS is also described as a micromachine or a micro electro mechanical device. MEMS corresponds to an electronic device in which a micro mechanical portion including “a movable micro structure having a three-dimensional structure” is combined with “an electric circuit including a semiconductor element” which controls the mechanical portion. In addition, MEMS is also simply called a micro machine.
Since a MEMS can control its micro structure by an electric circuit, it has been expected that an autonomous-distributed type system can be constructed instead of a central-processing control type system such as a conventional device using a computer. For example, a MEMS can process data obtained by a sensor by using an electric circuit and can drive an actuator or the like in accordance with data processing.
Many researches have been made on a micro machine. For example, an advanced MEMS wafer level package has been proposed to solve a problem that a manufacturing process cannot be used in facilities for wafer manufacturing and plastic assembly in Reference 1 (Japanese Published Patent Application No. 2001-144117). Reference 2 (Japanese Published Patent Application No. 2004-1201) discloses that preferable mechanical characteristics are generated in a layer which forms a structure by controlling laser irradiation.
However, as disclosed in Reference 1, a micro structure which forms a micro machine is manufactured in a manufacturing process of a semiconductor element using a silicon wafer. In particular, in order to obtain a material having thickness and intensity enough for manufacturing of a micro structure, micro machines which are practically used are mainly manufactured by using silicon wafers. In addition, Reference 2 discloses only a cantilever which is a micro structure but dose not disclose integration of the micro structure with an electric circuit at all.